| Tissue Specificity | Monocytic/myeloid lineage cells. In the brain, CD33 is mainly expressed on microglial cells. |
| Post Translational Modifications | Glycosylated. Glycosylation at Asn-100 is critical for regulating ligand recognition. Phosphorylation of Tyr-340 is involved in binding to PTPN6 and PTPN11. Phosphorylation of Tyr-358 is involved in binding to PTPN6. LCK phosphorylates Tyr-340 efficiently and Tyr-358 to a lesser extent. |
| Function | Sialic-acid-binding immunoglobulin-like lectin (Siglec) that plays a role in mediating cell-cell interactions and in maintaining immune cells in a resting state. Preferentially recognizes and binds alpha-2,3- and more avidly alpha-2,6-linked sialic acid-bearing glycans. Upon engagement of ligands such as C1q or syalylated glycoproteins, two immunoreceptor tyrosine-based inhibitory motifs (ITIMs) located in CD33 cytoplasmic tail are phosphorylated by Src-like kinases such as LCK. These phosphorylations provide docking sites for the recruitment and activation of protein-tyrosine phosphatases PTPN6/SHP-1 and PTPN11/SHP-2. In turn, these phosphatases regulate downstream pathways through dephosphorylation of signaling molecules. One of the repressive effect of CD33 on monocyte activation requires phosphoinositide 3-kinase/PI3K. |
| Protein Name | Myeloid Cell Surface Antigen Cd33Sialic Acid-Binding Ig-Like Lectin 3Siglec-3Gp67Cd Antigen Cd33 |
| Database Links | Reactome: R-HSA-198933Reactome: R-HSA-6798695 |
| Cellular Localisation | Isoform Cd33m: Cell MembraneSingle-Pass Type I Membrane ProteinIsoform Cd33m: PeroxisomeCd33m Isoform Does Not Localize To Cell Surfaces But Instead Accumulates In Peroxisomes |
| Alternative Antibody Names | Anti-Myeloid Cell Surface Antigen Cd33 antibodyAnti-Sialic Acid-Binding Ig-Like Lectin 3 antibodyAnti-Siglec-3 antibodyAnti-Gp67 antibodyAnti-Cd Antigen Cd33 antibodyAnti-CD33 antibodyAnti-SIGLEC3 antibody |
Information sourced from Uniprot.org
